"The study fills a gap. We wanted to know how many American adults really meet the guidelines for all of these risk factors and are within optimal levels for disease prevention and health," said study first author Joana Araujo. She is a postdoctoral research associate in nutrition.

"Based on the data, few Americans are achieving metabolic health, but the most disturbing finding was the complete absence of optimal metabolic health in adults who had obesity, less than a high school education, were not physically active and were current smokers," Araujo said in a university news release.

For the new study, the researchers analyzed data from more than 8,700 adults who took part in the U.S. National Health and Nutrition Examination Survey between 2009 and 2016. Just over 12 percent had good metabolic health, the investigators found.

Factors associated with better metabolic health included being physically active, female, younger, more educated and not smoking.

Factors associated with poorer metabolic health included being black and heavy. Less than 1 percent of obese adults are metabolically healthy, the researchers noted.